Improvement in bit-braces



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JOHN ,T.LYNAM, or lJarreRsoNviLLn, INDIANA.

Letters Patent No. 113,680, dated April 11, 1871.

IMPROVEMENT |N BIT-BRACES.-

The Schedule referred .to in 'ther-1e. Letters Patent and making part ofthe same.

and exact description thereof, which will enable others skilled in theart to make and use the same, reference being had to the accompanyingdrawing forming part of this speccation, in which- Figure 1 represents asectional side View of proved bit-brace.

Figure 2 is a horizontal section of the same taken on the plane of theline :c x, fig. l.

.Similar letters of reference indicate corresponding arts.

p The object of this invention is tol provide an improvement in ratchetbit-braces, or those which can be oscillated in either direction; and

The invention consists in the construction and arrangement of parts, vashereinafter described.

A in the drawing represents the brace, of ordinary or suitableconstruction.

A B is the bit-holder or shank. It is swiveled in the lower arm of thebrace, so that it can freely turn in the same.

` a is a toothed wheel, mounted upon the upper part ofthe shank B.

b b are two spring lpawls, secured to the brace A in such manner thattheir free ends fit against opposite sides of the wheel'a, locking thesame and preventing it from turning in either direction.

Between the. spring pawls b is arranged on the brace an arbor, c, whichcarries a projecting cam, el.

This arbor can be turned whenever desired to carry my imits cam dagainst either one of the spring pawls, moving the same ofi` theratchet-wheel.

Whenever one pawl is thrownofi' the ratchet-wheel the same is liberatedso that it-can be turned to one side butA not to the other. The bracecan then be used to apply the bit vby an oscillating movement, and alsoto withdraw the same, by throwing the cam against the opposite spring.

e is a block or plate aflixed to the brace between the spring pawls,and'serving as a support for the'- same, while they play inthe revolvingratchet-wheel.

Two jaws are placed in the socket B for the purpose of holding the bit.One of said jaws has a pin projecting from its inner end and face,passing through the end ofthe opposite jaw, and working in the sere'thread cut on theuner surface ofthe socket.

Thus it will he seen that when the bit-shank is inserted between thejaws and a rotary motion given to the same or to the socket B, the jawsmay be made to grasp and hold the bit very firmly by reason of theirconical surfaces coming in contact with the inner wall of the socket..

Having thus described my invention,

I claim as new and desire 'to secure by Letters Patenty The .bit-holderB, having swiveled shank with toothed wheel a thereon, combined with apair of spring pawls, b b, held apart by a plate, e, and operated by acam, Il, to lock the bit-holder, as set forth.

JOHN T. LYNAM.

Witnesses:

GEO. A. Hrnns, Gao. D. WlLLmMsoN.

